That's fine, but it isn't clear why XML must be able to support directed
graphs at its most basic level. We know that we need multiple levels to
support multiple types of structures.
We also know that one of the requirements for supporting directed graphs
*properly* is the ability to do relative addressing (that's why we have
XPointer). But ID/IDREF can't do that. ID/IDREF also has a very inflexible
namespace mechanism. Strictly speaking it is "enough" in that every
element is addressable, but practically speaking it does not allow us to
express the structure explicitly enough.
<EMPLOYEE NAME="John_Smith" POSITION_ID="CEO" LOCATION_ID="ROOM_115">
This element has three unique identifiers, each unique in a different
namespace.
In other words, ID/IDREF strikes me as the kind of half-solution likely to
be thought up by someone corrupted by too much exposure to SQL and not
enough to documents. :) :) :)
Paul Prescod - ISOGEN Consulting Engineer speaking for only himself.
http://itrc.uwaterloo.ca/~papresco
Christmas shopping in a T-Shirt? Toto, I have a feeling we
aren't in Canada anymore.